William Heaton, 28, smiled nervously as he entered the plea. He admitted to accepting favors from convicted lobbyist Jack Abramoff or his associates and then, in return, helping their clients.

Heaton served as Ney's chief of staff from 2002 through 2006, when the Ohio Republican resigned. Heaton traveled with Ney on a trip to Scotland paid for in part by Abramoff.

According to federal court documents filed Monday, Heaton's conspiracy charge involves that trip and others. Prosecutors say he also helped Ney solicit and conceal gifts given by lobbyists.

``Heaton and Ney solicited and accepted a stream of things of value from Abramoff and his lobbyists, including overseas and domestic trips, meals and drinks, golf, tickets to professional sporting events and concerts, and monetary and in-kind campaign contributions from Abramoff,'' prosecutors wrote.

Ney, R-Ohio, was sentenced to 2 years in prison in January for trading political favors for golf trips, campaign donations and other gifts in the Abramoff lobbying scandal. He was the first congressman charged in the affair.